Free Water Knockout

Free Water Knockout

After leaving the first stage vertical separator‚ the high pressure liquid portion of the produced fluid stream is directed towards the FWKO pressure vessel. This long‚ horizontal device is used to separate free water from degassed crude oil and crude oil-water emulsions‚ due to the differences in the densities of these mediums. Depending on the distance to this device‚ which is normally located at the Central Processing Facility‚ pumping may be required to boost the liquid to the inlet connection of this vessel. As the liquid enters the vessel the design residence time allows a large portion of the water to separate from the crude‚ collecting in the lower portion of the vessel. The captured water is pumped away for ultimate re-use in water flooding re-injection. The partially processed oil is now available for forwarding to the Heater Treater system.

As experience bears out‚ FWKO processes have their challenges. The basic operation of the system is designed around reasonably steady-state production conditions. In reality these seldom happen. Both high and low flow rates adversely impact the ability of the crude oil and water to effectively separate. Similarly the incoming crude at times has not been suitably degassed‚ so undesirable free gas is carried through the entire process. To minimize the vessel size and the elevation above grade‚ the FWKO pumps typically have very difficult suction conditions. When you factor in the inevitable presence of solid particulates‚ waxes‚ paraffins and even H2S in the process fluid‚ the pumps in this system face very demanding services every day.

Have you considered the value of using rotary PD pumping technology?

Upstream facility managers and operators around the globe have realized that volumetric‚ rotary PD pumps are something they can capitalize on in these services. Having a machine that can reliably handle variable inlet and outlet conditions with non-homogeneous‚ gas-laden (sour and sweet)‚ and contaminated‚ viscous process fluids is critical. These strengths‚ coupled with the tremendous turndown flow capabilities of rotary PD pumps‚ make them an ideal fluid-conveying solution for your FWKO systems.

Suitable pump types:

Progressing Cavity Pumps and Two-Screw Pumps